Abstract : Equations were developed to predict the thermal and mechanical properties required for a pressurized, polymeric frontal enclosure envelope (FEE) on a missile or aircraft as a function of mission requirements. It appears that a state-of-the-art, composite polymer insulator can be used as a pressurized FEE with a thickness less than 0.1 in. to satisfy a mission of Mach 3 at 5,000 ft altitude for some 3 minutes. The thermal and mechanical properties needed for a thickness of 0.05 in. and longer (ten minutes) or shorter times are given as examples of the practical use of the proposed design analysis. The analytical approach presented is intended primarily for specifying thermal and mechanical property requirements for polymeric materials. (Author, modified-PL)